610 BACTERIOLOGY. 



Stains readily with the ordinary aniline dyes, but 

 not by Gram's method. 



Biological Characters. A motile, facultative anaero- 

 bic, non-liquefying bacillus. Does not form spores as 

 far as known. Grows readily in all the ordinary cul- 

 ture media, at the room-temperature, but best at 37 C. 

 iu the incubator. On yelatin plates it forms rounded 

 colonies, transparent and granular It never liquefies 

 gelatin. In bouillon the bacillus grows quickly, without 

 forming either a pellicle or deposit. On blood-serum 

 its growth is almost imperceptible. Cultures on agar 

 are characteristic, according to Sanarelli. When the 

 colonies grow in the incubator they present an appear- 

 ance that does not differ from many other species; they 

 are rounded, of a slightly iridescent gray color, trans- 

 parent, even in surface, and regular in outline. Grown 

 at the room-temperature from 20 to 22 C., they ap- 

 pear like drops of milk, opaque, projecting, and with 

 pearly reflections, completely distinct from those grown 

 in the incubator. These different modes of evolution 

 Sanarelli considers to be an important diagnostic point; 

 first exposing the cultures for from twelve to sixteen 

 hours to the temperature of the incubator, and after- 

 ward for twelve to sixteen hours more to the tempera- 

 ture of the air. 



The bacillus icteroides ferments glucose and sacch- 

 arose, but does not coagulate milk; produces little 

 indol, and is quite resistant to desiccation; it dies in 

 water at 60 C., or after being exposed for seven hours 

 to the sunlight, and lives for a long time in sea-water. 



Pathogenesis. It is pathogenic for the greater num- 

 ber of the domestic animals; but birds are completely 

 refractory. According to the discoverer the dog lends 



